Global warming may boost snowfall in the Arctic, according to the results of research. Lakebed sediment cores such as this, held by researcher Elizabeth Thomas, indicate historic snowfall in Greenland has increased in times of warmer temperature. Courtesy: Douglas Levere

Global warming may increase Arctic snowfall which could slow the shrinkage of the Greenland ice sheet. A history of Arctic snowfall is hidden in ancient leaf waxes found in lake sediments on Greenland. A surprising trove of data yields indications of increased Arctic snowfall in times of warming.

by Charlotte Hsu, University at Buffalo

The history of Greenland’s snowfall is chronicled in an unlikely place: the remains of aquatic plants that died long ago, collecting at the bottom of lakes in horizontal layers that document the passing years.

Using this ancient record, scientists are attempting to reconstruct how Arctic precipitation fluctuated over the past several millennia, potentially influencing the size of the Greenland Ice Sheet as the Earth warmed and cooled.

An early study in this field finds that snowfall at one key location in western Greenland may have intensified from 6,000 to 4,000 years ago, a period when the planet’s Northern Hemisphere was warmer than it is today.

Global Warming Could Arctic Snowfall

While more research needs to be done to draw conclusions about ancient precipitation patterns across Greenland, the new results are consistent with the hypothesis that global warming could drive increasing Arctic snowfall — a trend that would slow the shrinkage of the Greenland Ice Sheet and, ultimately, affect the pace at which sea levels rise.

“As the Arctic gets warmer, there is a vigorous scientific debate about how stable the Greenland Ice Sheet will be. How quickly will it lose mass?” says lead researcher Elizabeth Thomas, PhD, an assistant professor of geology in the University at Buffalo College of Arts and Sciences who completed much of the study as a postdoctoral fellow at the University of Massachusetts Amherst.

“Climate models and observations suggest that as temperatures rise, snowfall over Greenland could increase as sea ice melts and larger areas of the ocean are exposed for evaporation. This would slow the decline of the ice sheet, because snow would add to its mass,” Thomas says. “Our findings are consistent with this hypothesis. We see evidence that the ratio of snow to rain was unusually high from 6,000 to 4,000 years ago, which is what you would expect to see if sea ice loss causes snowfall to increase in the region.”

Abstract

Precipitation is predicted to increase in the Arctic as temperature increases and sea ice retreats. Yet the mechanisms controlling precipitation in the Arctic are poorly understood and quantified only by the short, sparse instrumental record. We use hydrogen isotope ratios (δ2H) of lipid biomarkers in lake sediments from western Greenland to reconstruct precipitation seasonality and summer temperature during the past 8 kyr. Aquatic biomarker δ2H was 100‰ more negative from 6 to 4 ka than during the early and late Holocene, which we interpret to reflect increased winter snowfall. The middle Holocene also had high summer air temperature, decreased early winter sea ice in Baffin Bay and the Labrador Sea, and a strong, warm West Greenland Current. These results corroborate model predictions of winter snowfall increases caused by sea ice retreat and furthermore suggest that warm currents advecting more heat into the polar seas may enhance Arctic evaporation and snowfall.

Citation

Thomas, E. K., J. P. Briner, J. J. Ryan-Henry, and Y. Huang (2016); A major increase in winter snowfall during the middle Holocene on western Greenland caused by reduced sea ice in Baffin Bay and the Labrador Sea;Geophysical Research Letters, 43, doi:10.1002/2016GL068513.

It’s true that most of the ice mass can be lost, but on the other pole more mass will form. This shift is inevitable with the tectonic movement and the axis angle of earth. This is a natural process that cycles in 50-70 thousand years.